Mercer County, Kentucky
Shrink-swell clay limits houses without basements on 22% of Mercer County's mapped land, a higher share than 72% of US counties. A shallow water table limits basements on 4%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 35 flood losses here since 2016, 21% of them in buildings with basements. 54% of homes were built before 1980, against 50% nationally; the median home dates from 1978.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Mercer County
| Expansive clay (limits slab homes) | 21.8% |
| High water table (limits basements) | 3.7% |
| Septic fields very limited | 82.6% |
| Clay swell (LEP, by area) | 4.8% |
| High-swell land (LEP 6%+) | 17.0% |
| Mapped soil | 162,061 acres |
How we count · survey areas KY606 (2025-09-08)
What the numbers mean here
Clay swell averages a linear extensibility of 4.8% by land area here, and 17% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 22% of the mapped land.
Rain over the 12 months to August 2026: 54.07 in, 4.25 in above the 1991-2020 average year of 49.82 in.
USDA rates 83% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 11 of the last 52 weeks; the most was 100% of its area, in 7 weeks, most recently on the May 26, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
35 flood losses since 2016, $1.6 million paid. The worst year was 2025, with 23. Foundations of the buildings, where recorded: 21% basements, 27% slabs, 12% crawl spaces, 39% elevated. Median water depth outside the building: 46 in.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 2 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 3 |
| 2022 | 0 |
| 2023 | 1 |
| 2024 | 1 |
| 2025 | 23 |
| 2026 to date | 5 |
Rain
| Average year, 1991-2020 | 49.82 in |
| 12 months to August 2026 | 54.07 in (+4.25) |
| 2025 | 67.61 in (+17.79) |
| Wettest year since 1895 | 2011: 68.41 in |
| Driest year since 1895 | 1930: 27.95 in |
| Days with 1 inch or more, normal at DIX DAM (10 mi away) | 11.3 |
Homes
| Housing units | 10,472 |
| Median year built | 1978 |
| Built before 1980 | 54% |
| Built 2000 or later | 26% |
| Owner-occupied | 76% |
| Median value, owner-occupied | $202,300 |
| Single-family detached | 80% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Boyle County, KY | 13 mi | 20% | 5% |
| Anderson County, KY | 15 mi | 25% | 4% |
| Washington County, KY | 17 mi | 23% | 5% |
| Jessamine County, KY | 17 mi | 27% | 4% |
| Woodford County, KY | 17 mi | 31% | 4% |
| Garrard County, KY | 22 mi | 18% | 5% |
| Lincoln County, KY | 27 mi | 8% | 14% |
| Marion County, KY | 28 mi | 5% | 14% |
Sources: USDA SSURGO (September 8, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status